Excluding very large ship diesels, the typical maximum efficiency of modern internal combustion engines (ICE) is only about 30-35%. Because this efficiency is only attainable in a narrow band of loads (normally close to full load) and because most vehicles typically operate at partial load around 70% to 90% of the times, it should not be surprising that overall, or “well to wheel,” efficiency is only 12.6% for city driving and 20.2% for highway driving for typical mid-size vehicle.
There is prior art in which a Homogeneous Charge Compression Ignition (HCCI) cycle offers to improve the efficiency of internal combustion engines. While offering some advantages over existing engines, they too, however, fall short in providing high maximal efficiency. In addition, HCCI cycle engines also are polluting (particulate matter) and are difficult and costly to control because the ignition event is spontaneous and function of great many variables such as pressure, temperature, exhaust gas concentration, water vapor content, etc.